A disc permanent magnet eddy current coupling with small torque fluctuation

Abstract

The present invention discloses a disc-type permanent magnet eddy current coupling with small torque fluctuation, which comprises a driving shaft, a driving disc, a driven shaft and a driven disc; the driving disc includes a back iron disc I, a plurality of magnets and a magnetic induction disc with iron blocks, the back iron disc I and the magnetic induction disc are coaxially arranged and connected through a connecting column III, the back iron disc I is circular ring-shaped, the magnets are sector-shaped and are fixed on the inner surfaces of the back iron disc I and the magnetic induction disc facing each other, and the back iron disc I and the driving shaft are connected through a connecting column I; the driven disc is located between the back iron disc I and the magnetic induction disc and is coaxially arranged with the two, the driven disc includes an eddy current disc and a back iron disc II, the eddy current disc and the back iron disc II are closely attached together, the driven shaft passes through the magnetic induction disc, the inner holes of the eddy current disc and the back iron disc II are matched with the shaft sections of the driven shaft, and are fixedly connected with the flange part of the driven shaft through a connecting column II. The torque transmitted between the driving disc and the driven disc of the present invention increases, and the torque fluctuation decreases.

Description

Technical Field

[0001] The present invention relates to permanent magnet eddy current drive technology, and particularly to a permanent magnet eddy current coupling. Background Art

[0002] Permanent magnet eddy current drive technology has been widely applied in industrial production, mainly in the transmission fields of high-power fans, pumps and other loads in fields such as steel, coal, petroleum, and metallurgy, and has the advantages of energy conservation, long service life, and simple maintenance. Using high-performance neodymium iron boron permanent magnets can increase the axial air-gap magnetic density, reduce the volume of the device, and save occupied space. Since there is no rigid coupling between shafts during torque transmission, the device has the characteristics of absorbing vibration, buffering starting, overload protection, and tolerating misalignment deviation, greatly improving the applicability and reliability of the device operation.

[0003] The basic principle of permanent magnet eddy current drive technology is: when the permanent magnet rotor and the eddy current ring rotor make relative rotational motion, the permanent magnets with alternately arranged magnetic pole directions on the permanent magnet rotor will generate an alternating magnetic field in the eddy current ring made of conductive material, and then an alternating eddy current will be induced therein. This eddy current generates an induced magnetic field in the eddy current ring. The induced magnetic field interacts with the magnetic field on the permanent magnet rotor, and a coupling torque is generated between the two rotors, thereby achieving the function of transmitting motion and torque.

[0004] The structural forms of permanent magnet eddy current drive devices mainly include sleeve type and flat plate type at present, and their application fields mainly include permanent magnet eddy current couplings (drivers) and permanent magnet eddy current speed regulators.

[0005] The existing disc-type permanent magnet eddy current coupling consists of a driving disc and a driven disc. The driving disc consists of a back iron disc and magnets, and the driven disc consists of an eddy current disc and a back iron disc. This structural solution has the following disadvantages: First, the air-gap magnetic flux density distribution curve is not sufficiently sinusoidal, and there are many torque fluctuations, so it cannot meet the requirements in actual applications, especially in precise occasions where torque fluctuations are required to be limited; Second, the magnetic leakage is large, so the utilization efficiency of magnetic materials is low; Third, the proportion of ineffective eddy currents in the conductor area that do not contribute to torque generation is large, and the degree of eddy current aggregation is insufficient, thus increasing the redundant eddy current loss. Since the eddy current loss is the main power loss of the permanent magnet eddy current drive device, the utilization efficiency of magnetic materials is reduced. Summary of the Invention

[0006] The problem to be solved by the present invention is to provide a disc-type permanent magnet eddy current coupling, which increases the torque transmitted between the driving disc and the driven disc and reduces the torque fluctuation. At the same time, the magnetic leakage between the driving disc and the driven disc is reduced, and the utilization efficiency of magnetic materials is improved. In addition, the coupling operates stably.

[0007] The present invention relates to a disc-type permanent magnet eddy current coupling with small torque fluctuation, which comprises a driving shaft, a driving disc, a driven shaft and a driven disc. The driving shaft and the driving disc are coaxially arranged and connected to each other. The driven shaft and the driven disc are coaxially arranged and connected to each other. The driving disc and the driven disc are coaxially arranged. The driving disc includes a back iron disc I, a plurality of magnets, and a magnetic induction disc with iron blocks. The back iron disc I and the magnetic induction disc are coaxially arranged and connected by a connecting column III. The back iron disc I is circular ring-shaped. The magnets are fan-shaped and are fixed on the inner surface opposite to the magnetic induction disc of the back iron disc I. The back iron disc I and the driving shaft are connected by a connecting column I. The driven disc is located between the back iron disc I and the magnetic induction disc and is coaxially arranged with them. The driven disc includes an eddy current disc and a back iron disc II. The eddy current disc and the back iron disc II are closely attached to each other. The eddy current disc is opposite to the back iron disc I, and the back iron disc II is opposite to the magnetic induction disc. The driven shaft passes through the magnetic induction disc. The inner holes of the eddy current disc and the back iron disc II are matched with the shaft section of the driven shaft and are fixedly connected to the flange part of the driven shaft through a connecting column II.

[0008] Further, the magnetic induction disc includes a fixing disc, a plurality of iron blocks I, and a plurality of iron blocks II. The fixing disc is circular ring-shaped, and a plurality of fan-shaped grooves are arranged on its annular surface. The iron blocks I and the iron blocks II are both fan-shaped and are respectively arranged in the fan-shaped grooves.

[0009] Further, the magnets are evenly distributed on the back iron disc I to form an annular array; the fan-shaped grooves on the fixing disc form an annular array, and the iron blocks I and the iron blocks II also form an annular array; the positions of the iron blocks I and the iron blocks II correspond to the positions of the magnets.

[0010] Further, when the size of the iron block I is larger than the size of the iron block II, the fan-shaped grooves on the fixing disc are stepped grooves, and the iron blocks I and the iron blocks II are respectively arranged in the fan-shaped stepped grooves.

[0011] Further, the back iron disc I is a disc body that is integrally circular and has a circular hole in the center, or it can also be a disc body that is integrally circular and does not have a circular hole in the center.

[0012] Further, the material of the magnet 6 is neodymium iron boron, magnetized along the axial direction. The magnet is composed of a permanent magnet with an even number of magnetic poles, and the permanent magnet array adopts an N, S pole alternating distribution magnetic pole array or a halbach permanent magnet array.

[0013] Further, the material of the eddy current disc is a conductive material, preferably a copper disc; the material of the fixing disc 11 is a non-magnetic material, preferably aluminum.

[0014] Further, the total cross-sectional area of the magnets is 60%-90% of the cross-sectional area of the back iron disc I, and the magnets are bonded to the back iron disc I.

[0015] Further, the total cross-sectional area of the iron blocks I and the iron blocks II is 60%-90% of the cross-sectional area of the back iron disc II, and the iron blocks I and the iron blocks II are bonded or clamped to the fixing disc.

[0016] Furthermore, the distance between the fixed disk 11 and the back iron disk II 9 is 3 mm - 5 mm.

[0017] The advantages of the disk-type permanent magnet eddy current coupling of the present invention are as follows: Since the positions of the magnets correspond to the positions of the iron blocks on the induction disk and the two operate synchronously, the iron blocks change the local magnetic field, causing the magnetic induction lines corresponding to the magnets to converge towards their direct opposite, and the air-gap magnetic flux density tends to be sinusoidally distributed. At the same time, because the thickness of the back iron disk is sufficient, the magnetic induction lines will not overflow or only a small amount will overflow. Therefore, the torque transmitted between the driving disk and the driven disk increases, and the torque fluctuation decreases. At the same time, the iron blocks change the local magnetic field, causing the magnetic induction lines corresponding to the magnets to converge towards their direct opposite, resulting in a reduction in the magnetic leakage between the driving disk and the driven disk, thereby improving the utilization efficiency of the magnetic material. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is an exploded view of the disk-type permanent magnet eddy current coupling of the present invention;

[0019] Figure 2 is a schematic diagram of the induction disk in the present invention;

[0020] Figure 3 is a cross-sectional view of the disk-type permanent magnet eddy current coupling of the present invention;

[0021] Figure 4 is a schematic diagram of the magnetic field distribution principle of the disk-type permanent magnet eddy current coupling of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0022] The present invention will be further described in detail below with reference to the drawings and embodiments.

[0023] Embodiment 1

[0024] From Figure 1 , Figure 2It can be seen that for the disc-type permanent magnet eddy current coupling of the present invention, it includes a driving shaft 3, a driving disc 1, a driven shaft 4, and a driven disc 2. The driving shaft 3 and the driving disc 1 are coaxially arranged and connected to each other. The driven shaft 4 and the driven disc 2 are coaxially arranged and connected to each other. The driving disc 1 and the driven disc 2 are coaxially arranged. The driving disc 1 includes a back iron disc I 5, a plurality of magnets 6, and an induction disc 7 with iron blocks. The back iron disc I 5 and the induction disc 7 are coaxially arranged and connected by a connecting column III 15. The back iron disc I 5 is circular ring-shaped. The magnets 6 are sector ring-shaped and are fixed on the inner surface opposite to the induction disc 7 of the back iron disc I 5. The back iron disc I 5 and the driving shaft 3 are connected by a connecting column I 13. The driven disc 2 is located between the back iron disc I 5 and the induction disc 7 and is coaxially arranged with them. The driven disc 2 includes an eddy current disc 8 and a back iron disc II 9. The eddy current disc 8 and the back iron disc II 9 are closely attached together. The eddy current disc 8 is opposite to the back iron disc I 5, and the back iron disc II 9 is opposite to the induction disc 7. The driven shaft 4 passes through the induction disc 7. The inner holes of the eddy current disc 8 and the back iron disc II 9 are matched with the shaft section of the driven shaft 4 and are fixedly connected to the flange part of the driven shaft 4 through a connecting column II 14.

[0025] When the driving shaft 3 rotates relative to the driven shaft 4, the driving shaft 3 drives the driving disc 1 to rotate, and the back iron disc I 5 with magnets 6 rotates relative to the driven disc 2. Therefore, an alternating magnetic field is generated in the eddy current disc 8, and then an alternating eddy current is induced in it. This eddy current generates an induced magnetic field. The induced magnetic field interacts with the magnetic field on the permanent magnet rotor, that is, the magnets 6, so that a coupling torque is generated between the two rotors, thereby driving the driven disc 2 to rotate. While the back iron disc I 5 rotates relative to the driven disc 2, the induction disc 7 rotates synchronously with the back iron disc I 5 relative to the driven disc 2.

[0026] Since the iron block itself has the effect of attracting the magnetic field, in this structure, the positions of the magnets correspond to the positions of the iron blocks on the induction disc, and the two operate synchronously. The iron blocks change the local magnetic field, making the magnetic induction lines corresponding to the magnets gather towards their direct opposite, and the air-gap magnetic flux density tends to be sinusoidally distributed. At the same time, because the thickness of the back iron disc is sufficient, the magnetic induction lines will not overflow, or the overflow is very small. Therefore, the torque transmitted between the driving disc and the driven disc increases, and the torque fluctuation decreases. The iron blocks change the local magnetic field, reducing the magnetic leakage between the driving disc and the driven disc, thereby improving the utilization efficiency of the magnetic material.

[0027] Embodiment 2

[0028] From Figure 3It can be seen that for the disc-type permanent magnet eddy current coupling of the present invention, the induction disc 7 includes a fixing disc 11, a plurality of iron blocks I 10, and a plurality of iron blocks II 12. The fixing disc 11 is circular ring-shaped, and a plurality of fan-shaped grooves are provided on its annular surface. The iron blocks I 10 and the iron blocks II 12 are both fan-shaped and are respectively arranged in the fan-shaped grooves. The magnets 6 are evenly distributed on the back iron disc I 5 to form an annular array; the fan-shaped grooves on the fixing disc 11 form an annular array, and the iron blocks I 10 and the iron blocks II 12 also form an annular array; the positions of the iron blocks I 10 and the iron blocks II 12 correspond to the positions of the magnets 6.

[0029] While the back iron disc I 5 rotates relative to the driven disc 2, the induction disc 7 rotates synchronously with the back iron disc I 5 relative to the driven disc 2, that is, the fixing disc 11 provided with the iron blocks I 10 and the iron blocks II 12 rotates relative to the driven disc 2.

[0030] From Figure 4 It can be seen that since the iron block itself has the effect of attracting the magnetic field, in this structure, the positions of the magnets 6 correspond to the positions of the iron blocks I 10 and the iron blocks II 12. The magnets 6, the iron blocks I 10, and the iron blocks II 12 rotate synchronously. The iron blocks I 10 and the iron blocks II 12 change the local magnetic field, causing the magnetic induction lines corresponding to the magnets to gather towards their direct opposite, and the air-gap magnetic flux density tends to be sinusoidally distributed. The torque transmitted between the driving disc and the driven disc increases, and the torque fluctuation decreases. At the same time, the iron blocks I 10 and the iron blocks II 12 on the induction disc 7 change the local magnetic field, reducing the magnetic leakage between the driving disc and the driven disc, thereby improving the utilization efficiency of the magnetic material.

[0031] Embodiment 3

[0032] For the disc-type permanent magnet eddy current coupling of the present invention: when the size of the iron block I 10 is larger than the size of the iron block II 12, the fan-shaped grooves on the fixing disc 11 are stepped grooves, and the iron blocks I 10 and the iron blocks II 12 are respectively arranged in the fan-shaped stepped grooves.

[0033] In the present invention, the sizes of the iron blocks I 10 and the iron blocks II 12 can be the same, or the size of the iron block I 10 can be larger than the size of the iron block II 12.

[0034] Among them, as a preferred method, when the size of the iron block I 10 is larger than the size of the iron block II 12, the effect of changing the local magnetic field is more obvious, the magnetic leakage will be less, and the utilization efficiency of the magnetic material is further improved; at the same time, it also makes the air-gap magnetic flux density more tend to be sinusoidally distributed, and the torque transmitted between the driving disc and the driven disc further increases, and the torque fluctuation is smaller.

[0035] Embodiment 4

[0036] For the disc-type permanent magnet eddy current coupling of the present invention: the back iron disc I 5 is a disc body that is integrally circular and has a circular hole in the center, or it can also be a disc body that is integrally circular and does not have a circular hole in the center.

[0037] On the premise of not affecting the stability of the overall structure of the back iron disk I 5, the back iron disk I 5 can also be other disk structures.

[0038] Embodiment 5

[0039] In the disk-type permanent magnet eddy current coupling of the present invention: the magnet material is neodymium iron boron, the magnet is magnetized axially, the magnet is composed of permanent magnets with an even number of pairs of magnetic poles, and the permanent magnet array adopts a magnetic pole array with alternating N and S poles or a Halbach permanent magnet array.

[0040] The permanent magnets with alternating magnetic pole directions on the permanent magnet rotor will generate an alternating magnetic field in the eddy current ring made of a conductive material, and then an alternating eddy current will be induced in it. This eddy current will generate an induced magnetic field in the eddy current ring. The induced magnetic field interacts with the magnetic field on the permanent magnet rotor, thus generating a coupling torque between the two rotors, so as to achieve the function of transmitting motion and torque.

[0041] Embodiment 6

[0042] The material of the eddy current disk 8 is a conductive material, preferably a copper disk; the material of the fixed disk 11 is a non-magnetic material, preferably aluminum.

[0043] The total cross-sectional area of the magnet 6 is 60%-90% of the cross-sectional area of the back iron disk I 5, and the magnet 6 is bonded to the back iron disk I 5.

[0044] The total cross-sectional area of the iron block I 10 and the iron block II 12 is 60%-90% of the cross-sectional area of the back iron disk II 9, and the iron block I 10 and the iron block II 12 are bonded or clamped to the fixed disk 11.

[0045] Embodiment 7

[0046] The distance between the fixed disk 11 and the back iron disk II 9 is 3 mm - 5 mm.

[0047] When the distance between the fixed disk and the back iron disk II is within this range, the iron blocks on it make the magnetic induction lines corresponding to the magnets gather towards its exact opposite obviously, the air-gap magnetic flux density further tends to be sinusoidal distribution, so that the torque transmitted between the driving disk and the driven disk is further increased and the torque fluctuation is further reduced; at the same time, the magnetic leakage between the driving disk and the driven disk is further reduced, thus further improving the utilization efficiency of the magnetic material.

[0048] The advantages of the disc permanent magnet eddy current coupling of the present invention are as follows: First, by configuring a synchronously rotating induction disc, the air-gap magnetic density is increased, making the air-gap magnetic flux density tend to be sinusoidal, increasing the torque transmitted between the driving disc and the driven disc and reducing the torque fluctuation. Second, by configuring a synchronously rotating induction disc, the local magnetic field is changed, reducing the magnetic leakage and improving the utilization efficiency of magnetic materials. Third, by configuring a synchronously rotating induction disc, the degree of eddy current aggregation is increased, improving the utilization efficiency of magnetic materials. Fourth, the coupling can not only increase the output torque but also reduce the torque fluctuation, with an adaptive compensation function for torque, making the coupling tend to be stable during operation. Fifth, the coupling has no vibration transmission and low noise; since there is no direct contact between the driving shaft and the driven shaft, the driven shaft is basically not affected by the vibration of the driving shaft, separating the vibrations between the driving shaft and the driven shaft to reduce the generation of corresponding noise. Sixth, the eddy current coupling has no friction, does not require lubrication, and has no leakage; since there is no contact between the driving shaft and the driven shaft, lubrication is not required, thus eliminating the trouble caused by the leakage of lubricating oil.

Claims

1. A disc-type permanent magnet eddy current coupling with small torque fluctuation, which comprises a driving shaft (3), a driving disc (1), a driven shaft (4), and a driven disc (2). The driving shaft (3) and the driving disc (1) are coaxially arranged and connected to each other. The driven shaft (4) and the driven disc (2) are coaxially arranged and connected to each other. The driving disc (1) and the driven disc (2) are coaxially arranged. It is characterized in that: The driving disk (1) includes a back iron disk I (5), several magnets (6), and a magnetic induction disk (7) with iron blocks. The back iron disk I (5) and the magnetic induction disk (7) are coaxially arranged and connected by a connecting column III (15). The back iron disk I (5) is annular. The magnets (6) are sector-shaped and are fixed on the inner surfaces of the back iron disk I (5) and the magnetic induction disk (7) facing each other. The back iron disk I (5) is connected to the driving shaft (3) through a connecting column I (13). The driven disk (2) is located between the back iron disk I (5) and the magnetic induction disk (7) and is coaxially arranged with both. The driven disk (2) includes an eddy current disk (8) and a back iron disk II (9). The eddy current disk (8) and the back iron disk II (9) are closely attached together. The eddy current disk (8) faces the back iron disk I (5), and the back iron disk II (9) faces the magnetic induction disk (7). The driven shaft (4) passes through the magnetic induction disk (7). The inner holes of the eddy current disk (8) and the back iron disk II (9) are fitted with the shaft sections of the driven shaft (4) and are fixedly connected to the flange part of the driven shaft (4) through a connecting column II (14).

2. The disc permanent magnet eddy current coupling according to claim 1, characterized in that: The magnetic induction disk (7) includes a fixed disk (11), several iron blocks I (10), and several iron blocks II (12). The fixed disk (11) is annular, and several sector-shaped grooves are arranged on its annular surface. The iron blocks I (10) and the iron blocks II (12) are both sector-shaped and are respectively arranged in the sector-shaped grooves.

3. The disc permanent magnet eddy current coupling according to claim 2, characterized in that: The magnets (6) are evenly distributed on the back iron disk I (5) to form an annular array; the sector-shaped grooves on the fixed disk (11) form an annular array, and the iron blocks I (10) and the iron blocks II (12) also form an annular array; the positions of the iron blocks I (10) and the iron blocks II (12) correspond to the positions of the magnets (6).

4. The disc permanent magnet eddy current coupling according to claim 2, characterized in that: When the size of the iron block I (10) is larger than the size of the iron block II (12), the sector-shaped grooves on the fixed disk (11) are stepped grooves, and the iron blocks I (10) and the iron blocks II (12) are respectively arranged in the sector-shaped stepped grooves.

5. The disc permanent magnet eddy current coupling according to claim 1, characterized in that: The back iron disk I (5) is a disk body that is integrally circular and has a circular hole in the center.

6. The disc permanent magnet eddy current coupling according to claim 1, characterized in that: The back iron disk I (5) is a disk body that is integrally circular and does not have a circular hole in the center.

7. The disc permanent magnet eddy current coupling according to claim 1, characterized in that: The material of the magnet (6) is neodymium iron boron, magnetized along the axial direction. The magnet is composed of permanent magnets with an even number of pairs of magnetic poles, and the permanent magnet array adopts an N, S pole alternating distribution magnetic pole array or a halbach permanent magnet array.

8. The disc permanent magnet eddy current coupling according to claim 1, characterized in that: The material of the eddy current disk (8) is a conductive material; the material of the fixed disk (11) is a non-magnetic material.

9. The disc permanent magnet eddy current coupling according to claim 8, characterized in that: The material of the eddy current disk (8) is copper; the material of the fixed disk (11) is aluminum.

10. The disc permanent magnet eddy current coupling according to claim 1, wherein: The total cross-sectional area of the magnets (6) is 60%-90% of the cross-sectional area of the back iron disk I (5), and the magnets (6) are bonded to the back iron disk I (5).

11. The disc permanent magnet eddy current coupling according to claim 1, characterized in that: The total cross-sectional area of the iron blocks I (10) and the iron blocks II (12) is 60%-90% of the cross-sectional area of the back iron disk II (9), and the iron blocks I (10) and the iron blocks II (12) are bonded or clamped to the fixed disk (11).

12. The disk-type permanent magnet eddy current coupling according to claim 1, characterized in that: The distance between the fixed disk (11) and the back iron disk II (9) is 3mm - 5mm.

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